Irritable bowel syndrome is a common chronic functional bowel disorder which accounts for up to 50% of gastroenterology referrals. Prior work indicates that patients with IBS frequently report sleep problems including poor sleep quality, insomnia, and frequent awakenings. Consistent with self-report of increased arousal at night is higher levels of urinary catecholamines in early a.m. urine samples as compared to women without GI symptoms. A limited number of studies using polysomnography measures suggest that objective sleep may be different in IBS patients as compared to non-symptomatic individuals. The purposes of this study are to: (1) describe and compare indicators of sleep including (a) self report of sleep quality and (b) objective measures of sleep; (2) describe and compare specific factors which may account for self-report of or objective indications of sleep disruption: (a) neuroendocrine disruption of nighttime cortisol, serotonin; (b) indicators of autonomic nervous system imbalance, (c) indicators of psychological distress (i.e. psychopathology, recalled psychological distress, daily levels of psychological distress); and (3) explore and identify subtypes of women with IBS based on the clusters of self-reported poor quality of sleep, objective sleep, neuroendocrine disruption, ANS imbalance, and psychological distress.